The present invention relates to objects and their manufacture. More particularly, the invention is illustrated in an example using a novel combination of gases and a downstream plasma surface for selectively treating surfaces for substrates used in semiconductor integrated circuits. Merely by way of example, the invention can be applied in the manufacture of other substrates such as flat panel displays, micro electrical mechanical machines (“MEMS”), sensors, optical devices, and others.
In the manufacture of objects such as integrated circuits, processing safety and reliability have been quite important. Fabrication of integrated circuits generally requires numerous processing steps such as etching, deposition, photolithography, and others. In the manufacture of semiconductor wafers, there have been used or proposed a variety of surface treatment methods. For example, there have been several documents which reported material surface treatments using the reaction of atomic hydrogen processed by a hydrogen containing gas plasma. Japanese Patent KOKAI H7-75229 and U.S. Pat. No. 5,089,441 appeared to show an ashing method of organic materials, which was carbonized by ion implant, in a hydrogen plasma in which a concentration of atomic hydrogen was increased by adding water vapor into the hydrogen plasma.
U.S. Pat. No. 5,089,441 reported a dry cleaning method of a semiconductor surface, which was performed by setting an objective semiconductor substrate in a downstream of a plasma generated with a mixture of a hydrogen molecule and germanium (“GeH4”), hydrogen chloride, hydrogen bromide or hydrogen fluoride as the plasma gas source. Also it has been reported that the high concentration atomic hydrogen is obtained in plasma downstream area by the use of mixture of hydrogen and water vapor as the source gas for the plasma. (J. Kikuchi, S. Fujimura, M. Suzuki, and H. Yano), “Effects of H2O on atomic hydrogen generation in hydrogen plasma,” Jpn. J. Appl. Phys., 32, pp. 3120–3124 (1993)).
Conventional plasma processing techniques using hydrogen, however, often cause undesirable results. For example, oxygen bearing plasmas often cause physical and/or electrical damage to surfaces being treated. Additionally, higher high energy particles also cause charging and physical damage to the treatment chamber itself. Conventional plasma processing techniques are also often difficult to control and may lead to plasma damage. These and other limitations of conventional systems are discussed more fully below.
From the above, it is seen that a technique for improving surface treatment processes is provided.